Within the Erupter Fuzz's simple, one switch and one knob chassis is a monster of a pedal with a startling amount of power. The knob is billed as a "Bias" control that determines how much voltage is fed to the silicon transistors, which give the pedal a vintage vibe. The result is a surprisingly tweakable stompbox, capable of both smoothed out low–end fuzz as well as tinny high–end screams.